1. Field of the Invention
The present invention relates to a confocal scanning microscope and, more particularly, to improvements made to a light source unit for inputting light from a light source to an optical fiber.
2. Description of the Prior Art
Confocal scanning microscopes have heretofore been well-known. An example of a confocal optical scanner for use with a confocal scanning microscope, there is the one illustrated in FIG. 1 and described in the official gazette of Japanese Laid-open Patent Application 1993-60980, for example.
In FIG. 1, laser light emitted from laser light source 1 is first introduced to an excitation filter (not shown in the figure) to remove extra wavelength components of the light source so that only the wavelength component to be used for excitation is allowed to go out.
After being broadened to an appropriate beam diameter, this outgoing light (laser light) enters the microlens array of microlens array disk 2 in the scanner unit. Laser light thus entering the microlens array is condensed by each individual microlens onto each pinhole in pinhole disk 3 positioned in opposition to such each individual microlens.
As a result of condensation, the amount of light that can pass through pinhole disk 3 increases greatly. In addition, amounts of light (noise light), reflected on the parts of the disk surface other than the pinholes, decrease, thus improving the S/N ratio of images.
Dichroic mirror 4 is placed between microlens array disk 2 and pinhole disk 3, and excitation light passes through this dichroic mirror 4.
Laser light that has exited a pinhole in pinhole disk 3 passes through objective lens 5 and excites sample 6. Fluorescent light coming out of sample 6 passes through objective lens 5 and pinholes of pinhole disk 3, reflects upon dichroic mirror 4, and is introduced to an optical observation path system. The catoptric and stray components of excitation light mixed with fluorescent light going out of the scanner unit and entering the optical observation path system are removed by barrier filter 25. Then the fluorescent light enters high-sensitivity imaging camera 8 and fluorescent images of sample 6 are observed in the camera.
It should be noted that microlens array disk 2 and pinhole disk 3 are assembled into an integral structure so that the overall area under observation can be scanned by rotating the assembly.
In a conventional apparatus for confocal scanning microscopy such as that described above, the confocal optical scanner unit thereof is advantageous in that it is possible to improve the characteristics of image forming and reduce the amount of surface reflection from the pinhole disk surface. However, the scanner has only one excitation light source for irradiating samples, and the light source to be connected to the optical fiber must be changed in order to excite samples using light (laser) with a different wavelength.
FIG. 2 is a schematic view illustrating how laser light is input to a single mode optical fiber cable 15d by switching between light sources with wavelengths of, for example, 488 nm and 532 nm.
For the above-noted reason, the conventional apparatus has been problematic in that it is not possible to observe different types of fluorescence produced by other types of excitation lights simultaneously. Another problem is that extra time is required to attach and detach a light source to and from the optical fiber. Yet another problem is that vibration arising when the light source is attached to or detached from the optical fiber causes the sample to move.